P.R. wrote: > Hi, > I'd like to generate a colormap index based on an array of levels & using an > existing colormap (Spectral). > However, Id like the cmap index to start at the 0.3 value of the Spectral > scale (orange/yellow area) instead of starting at the '0' scale value (red > area), and then continue until the 0.8 value area (green)...in essence, Id > like to do a 'slice' of a given colormap, using BoundaryNorm or some other > function, and using my levels array in order to break up the colormap. > > What would be the best way to get this done? > Can it be easily done using existing functions, or would I need to create my > own colormap?
One way is to extract the colors you want from spectral, and use them with a boundary norm. Suppose you want 10 colors because you have 11 boundaries, and suppose they are in the range from 20 to 30: import numpy as np import matplotlib.pyplot as plt import matplotlib.colors as mcolors import matplotlib.cm as cm boundaries = np.linspace(20, 30, 11) colors = cm.spectral(np.linspace(0.3, 0.8, 10)) cmap = mcolors.ListedColormap(colors) norm = mcolors.BoundaryNorm(boundaries, cmap.N) z = 20 + np.random.rand(10,20)*10 plt.imshow(z, cmap=cmap, norm=norm) plt.colorbar() plt.show() So yes, you are creating your own colormap, but it is easy. Eric > > Please help, > > Thanks, > P.Romero > > > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day > trial. Simplify your report design, integration and deployment - and focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
